Ios Software Engineer

Xist4 IT Limited.; City Of London; Remote; GBP 80,000 - 100,000; Full time

Job summary

Xist4 IT Limited is seeking an iOS Software Engineer to build a production iOS app in Swift and SwiftUI, with AI features behind backend APIs. The role is fully remote across the UK, with a permanent contract and a salary range of £80,000 to £100,000.

You’ll work in a small, distributed team alongside backend and ML engineers. You’ll own the iOS client, manage async/await and concurrency, optimize performance, and ensure App Store readiness as the prototype product progresses.

Qualifications

• Production iOS apps built in Swift.
• SwiftUI on apps with real users.
• AI-powered features integrated into a mobile app and backend APIs.
• Async/await, concurrency and background tasks used in production.
• Performance or memory improvements achieved in production.
• Latency-aware design for non-deterministic behaviour in apps.
• App Store releases and production issues you have owned.
• UK work eligibility and right to work in the UK.

Responsibilities

• Build and maintain a production iOS app using Swift and SwiftUI.
• Integrate AI features via backend APIs and design states around them (streaming, loading, retries).
• Ensure stability, observability and App Store readiness of the iOS client.
• Collaborate with backend and ML engineers on API design and system behavior.

Skills

Swift

SwiftUI

AI integration

Async/await

Performance optimization

App Store delivery

UK work eligibility

Tools

CoreML

TensorFlow Lite

SPM

Remote configuration

SQL

NoSQL

Job description

iOS Software Engineer | Swift, SwiftUI, AI integrations | Fully remote, UK
£80,000 to £100,000. Permanent.
London. Fully remote across the UK.

An iOS role where the AI is the product, and how it feels in someone's hand is down to you. That includes the moments when it is slow, half-finished or unpredictable.

Our client is an early-stage AI product company building applications that get on with everyday tasks before you ask. The first product is at prototype stage, with launch still ahead, and the business is funded without depending on an upcoming round. You would be shaping the app before real users ever see it.

You’ll work in a small, distributed team alongside backend and ML engineers. The iOS client is yours to build and maintain. The AI capability sits behind backend APIs.

The honest bit: AI interactions fail in awkward ways. Latency, partial responses, retries, background work, battery use and App Store stability all matter here, and the trade-offs are yours to make.

The job
iOS. Build and maintain a production iOS application in Swift and SwiftUI. You’ll work with async/await, concurrency and background tasks, and keep performance, memory use and battery efficiency under control.
AI experience. Integrate AI-powered features through backend APIs and design the states around them: streaming responses, loading, partial failure, retries and fallbacks. You’ll also capture user signals and feedback so the team can judge what is working.
Production. Keep the application stable, observable and fit for the App Store. When something breaks, you help find the root cause instead of passing it on.
Team. Work closely with backend and ML engineers on API design, system behaviour and the line between what the model can do and what the app should show.

What you’ll bring
Essential:

• Production iOS applications built and maintained in Swift.
• SwiftUI used on an application that reached real users.
• AI-powered features integrated into a mobile application.
• Async/await, concurrency and background tasks used in production.
• Performance or memory problems you have diagnosed and improved.
• Features designed around latency, partial failure or non‑deterministic behaviour.
• App Store releases and production issues you have owned.
• Existing right to work in the UK.

Useful: CoreML, TensorFlow Lite, SPM, feature flags, remote configuration, SQL, NoSQL.

Who this suits
You are probably an iOS Engineer, Mobile Engineer or Senior iOS Engineer who still wants to write the code. You have shipped enough to know that a smooth demo and a reliable product are different things.

It won’t suit you if you want a settled spec and predictable behaviour. Here you design for responses that arrive late, in pieces or not at all, and you stay with the problem when it breaks in production.

Let’s talk

We welcome applicants from every background and will support reasonable adjustments.